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Hi cch,
Until the next release of OPeNDAP you will not be able to access your
ASCII file through OPeNDAP with Ferret. Here's why:
All filenames that begin with "http://" are read by Ferret
using the OPeNDAP-enabled netCDF library. In other words they look
like netCDF datasets to Ferret. ASCII files which are served using
OPeNDAP (as in your case) are transmitted using OPeNDAP "Sequences".
The current version of the OPeNDAP netCDF library cannot process Sequence
data. Variables which are transmitted inside of Sequences are simply
ignored. That is why you see a dataset that appears to contain no
variables.
To explore this further go to your Web browser and enter this URL:
http://127.0.0.1/cgi-bin/nph-dods/asc.dat.dds
The ".dds" on the end is a request to the OPeNDAP server to show you
the dataset structure.
What you can do, instead, since you are able to read the local file with
Ferret is:
Use the "FILE" command in Ferret to initialize the local dataset.
Use the "SAVE" command to save the variables into a netCDF dataset.
Put that netCDF file into the data area of your OPeNDAP server.
yes? USE http://127.0.0.1/cgi-bin/nph-dods/my_netcdf_file.nc
Hope this helps - steve
===========================================
cch wrote:
Thanks, Joe!The
results is shown below.
NOAA/PMEL TMAP
FERRET v5.53
Linux(g77) 2.4.x - 09/26/03
5-Apr-04 16:40 yes?
set data http://127.0.0.1/cgi-bin/nph-dods/asc.datyes?
show data
currently SET data sets:
1> http://127.0.0.1/cgi-bin/nph-dods/asc1.dat
(default) name
title
I
J
K
Lyes? I
am a new Ferret user.Thanks
for any help!
----- Original
Message -----
Sent: Tuesday,
April 06, 2004 2:16 AM
Subject:
Re: I can't access remote ascii data with DODS
Hi,
Ferret is DODS enabled such that it has a built-in DODS NetCDF client.
When Ferret sees 'http...' in the ffilename for the command 'SET
DATA filename' it assumes that the data is DODS served and the NetCDF
client takes over reading the data. The Ferret 'file' command expects
local files only.
Currently, the server at http://127.0.0.1/cgi-bin/nph-dods/
seems to be down. What results do you get when you use theh ferret
command,'SET DATA "http://127.0.0.1/cgi-bin/nph-dods/asc.dat"'?
Joe
------------------------
cch wrote:
Dear Ferret users,I have installed
the Ferret 5.53 with RetHat 7.3.The Ferret can read local NetCDF file or
read NetCDF file from DODS well. It can also read local ascii file, the
commands are shown below. yes? define axis/x=-5:4:1/unit=degree
xlong yes? define axis/y=-5:4:1/unit=degree ylat
yes? define grid/x=xlong/y=ylat gplants yse? file/var=v1/columns=10/grid=gplants
asc.dat yse? contour v1 The ascii file is attached and
the data contains one variable , two dimensions. Now, I want to read the
ascii file with DODS.The format file asc.fmt is attached.The browser shows
the DDS, DAS information using URL http://127.0.0.1/cgi-bin/nph-dods/asc.dat.dds
http://127.0.0.1/cgi-bin/nph-dods/asc.dat.dasgood.
But the error message as following occured. yes?
define axis/x=-5:4:1/unit=degree xlong yes? define axis/y=-5:4:1/unit=degree
ylat yes? define grid/x=xlong/y=ylat gplants
yse? file/var=v1/columns=10/grid=gplants "http://127.0.0.1/cgi-bin/nph-dods/asc.dat"
yse? contour v1 **TMAP ERR: non-existent or not on line
DATAFILE NOT FOUND
Data set: http://127.0.0.1/cgi-bin/nph-dods/asc.dat
Data file: http://127.0.0.1/cgi-bin/nph-dods/asc.dat
yes? Any suggestion for the problem? Thanks!
--
Steve Hankin, NOAA/PMEL -- Steven.C.Hankin@noaa.gov
7600 Sand Point Way NE, Seattle, WA 98115-0070
ph. (206) 526-6080, FAX (206) 526-6744
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